If you decide you need to disable IPv6 on a Windows computer for some reason, there are several ways you can do this. For example, if you want to disable IPv6 for a specific local area network (LAN) interface on a Windows computer, you can do so by deselecting Internet Protocol Version 6 (TCP/IPv6) on the Networking tab of the connection’s properties. Note, however, that performing this action does not disable IPv6 for either the loopback interface or any tunnel interfaces on the computer.
To disable specific types of IPv6 functionality for all interfaces on a Windows computer, perform the following steps:
1. Create a new DWORD registry value named DisabledComponents under the following registry key:
HKLM\SYSTEM\CurrentControlSet\Services\tcpip6\Parameters\
2. Create an eight-bit binary that defines the types of IPv6 functionality you want to disable by using the following information:
- Bit 0 Set this bit to 1 to disable all IPv6 tunnel interfaces—including ISATAP, Teredo, 6to4, and IP-HTTPS—or set it to 0 to leave all IPv6 tunnel interfaces enabled.
- Bit 1 Set this bit to 1 to disable all 6to4 tunnel interfaces, or set it to 0 to leave all 6to4 tunnel interfaces enabled.
- Bit 2 Set this bit to 1 to disable all ISATAP-based interfaces, or set it to 0 to leave all ISATAP-based interfaces enabled.
- Bit 3 Set this bit to 1 to disable all Teredo-based interfaces, or set it to 0 to leave all Teredo-based interfaces enabled.
- Bit 4 Set this bit to 1 to disable IPv6 for all nontunnel interfaces, including LAN and PPP interfaces, or set it to 0 to leave all nontunnel interfaces enabled.
- Bit 5 Set this bit to 1 to configure the default prefix table so that IPv4 is preferred over IPv6 when attempting to establish a network connection, or set it to 0 to leave IPv6 as the preferred network layer protocol.
- Bit 6 Leave this bit set to 0 because it is reserved for future use.
- Bit 7 Set this bit to 1 to disable all IP-HTTPS-based interfaces, or set it to 0 to leave all IP-HTTPS-based interfaces enabled.
3. Convert the binary number you created into hexadecimal form, and assign it as the value for the DisabledComponents registry value. Remember that bit 7 is the leftmost bit and bit 0 is the rightmost bit of the binary number.
4. Restart the computer to have the changes take effect.
For example, let’s say you want to disable both Teredo and 6to4 on a Windows computer but leave ISATAP and all other IPv6 functionality enabled. To do this, you need to assign values to bits 0 through 7 as follows:
- Bit 0 0
- Bit 1 1
- Bit 2 0
- Bit 3 1
- Bit 4 0
- Bit 5 0
- Bit 6 0
- Bit 7 0
The binary number 00001010 converted to hexadecimal form is 0xA, and this is the value you would assign to the DisabledComponents registry value.
Mitch Tulloch is a nine-time recipient of the Microsoft Most Valuable Professional (MVP) award and a widely recognized expert on Windows administration, deployment and virtualization. For more information see http://www.mtit.com. This tip was excerpted from his latest book Training Guide: Installing and Configuring Windows Server 2012 from Microsoft Press.
